public static Result POSTFormData(string url, string identifier, string FormData)
        {
            // Setup the POST data
            //string poststring = String.Format("qrCodeData=90320388203195564382");
            Result result = new Result();
            try
            {

                HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(url);

                httpRequest.Method = "POST";
                httpRequest.ContentType = "application/x-www-form-urlencoded";
                httpRequest.Headers.Add("secret", identifier);


                // Convert the post string to a byte array
                byte[] bytedata = System.Text.Encoding.UTF8.GetBytes(FormData);
                httpRequest.ContentLength = bytedata.Length;

                // Create the stream
                Stream requestStream = httpRequest.GetRequestStream();
                requestStream.Write(bytedata, 0, bytedata.Length);
                requestStream.Close();

                // Get the response from remote server
                HttpWebResponse httpWebResponse = (HttpWebResponse)httpRequest.GetResponse();
                Stream responseStream = httpWebResponse.GetResponseStream();

                System.Text.StringBuilder sb = new System.Text.StringBuilder();
                using (StreamReader reader = new StreamReader(responseStream, System.Text.Encoding.UTF8))
                {
                    string line;
                    while ((line = reader.ReadLine()) != null)
                    {
                        sb.Append(line);
                    }
                }

                result.ResultState = true;
                result.JsonString = sb.ToString();

            }
            catch (Exception ex)
            {
                result.ResultState = false;
                result.SqlError = ex.Message;
            }

            return result;
        }



            object theImg = dt.Rows[0]["Picture"];
if (!DBNull.Equals(theImg, DBNull.Value) && ((byte[])theImg).Length > 0)
            {
                 pictureBox1.BackgroundImage = new ImageHelper().ByteToImage((byte[])theImg);
}